The UK contribution to the NAEWCF is/was via our jets and personnel so we've never paid for any NATO 'stuff.'Not free, they may have been funded by us originally so only reallocation of debt
Iirc, the consoles on the bent jet were written off by NATO and were due to be scrapped. However, we checked them and realised they were fine for use in the sim once they'd been modified to E-3D standard (different comms panel). That allowed 7 sim consoles to be removed, have the oxygen system plumbing added, and used as a tenth console on our jets!
To the best of my knowledge, we never paid a penny for them as NATO considered them scrap!